Fan blade having closed metal sheath

Abstract

A blade for use in a gas turbine engine is disclosed. In various embodiments, the blade includes a pressure side sheath and a suction side sheath secured to the pressure side sheath. The pressure side sheath and the suction side sheath are configured to form a continuous sheath that wraps around an interior section of the blade.

What is claimed is: 
     
       1. A blade for use in a gas turbine engine, comprising:
 a pressure side sheath; 
 a suction side sheath secured to the pressure side sheath; 
 wherein the pressure side sheath and the suction side sheath are configured to form a continuous sheath that wraps around an interior section of the blade; 
 wherein at least one of the pressure and suction side sheaths includes a base, a tip, and a central rib extending spanwise from the base to the tip such that a first cavity and a second cavity are established on opposed sides of the central rib; and 
 a structural core having a first core member in the first cavity and a second core member in the second cavity, and the structural core including a root that interconnects the first and second core members. 
 
     
     
       2. The blade of  claim 1 , wherein the pressure side sheath includes a leading edge portion and a trailing edge portion and wherein the suction side sheath is configured to mate against the leading edge portion and the trailing edge portion. 
     
     
       3. The blade of  claim 2 , wherein the leading edge portion includes a first pressure side sheath edge and wherein the trailing edge portion includes a second pressure side sheath edge. 
     
     
       4. The blade of  claim 3 , wherein the suction side sheath includes a first suction side sheath edge configured to mate with the first pressure side sheath edge and a second suction side sheath edge configured to mate with the second pressure side sheath edge. 
     
     
       5. The blade of  claim 4 , wherein the first suction side sheath edge extends from a suction side base of the suction side sheath to a suction side tip of the suction side sheath and wherein the first pressure side sheath edge extends from a pressure side base of the pressure side sheath to a pressure side tip of the pressure side sheath. 
     
     
       6. The blade of  claim 5 , wherein the second suction side sheath edge extends from the suction side base of the suction side sheath to the suction side tip of the suction side sheath and wherein the second pressure side sheath edge extends from the pressure side base of the pressure side sheath to the pressure side tip of the pressure side sheath. 
     
     
       7. The blade of  claim 1 , wherein the pressure side sheath includes a leading edge portion and a trailing edge portion and wherein the first cavity is positioned between the leading edge portion and the central rib and the second cavity is positioned between the trailing edge portion and the central rib. 
     
     
       8. The blade of  claim 7 , wherein the root is configured for attachment to a rotor hub or a rotor disk. 
     
     
       9. The blade of  claim 8 , wherein the structural core comprises a carbon based composite material. 
     
     
       10. The blade of  claim 9 , wherein the suction side sheath and the pressure side sheath are formed of a metal or metal alloy. 
     
     
       11. The blade of  claim 10 , wherein the root, the first core member and the second core member form a unitary, monolithic component constructed of a carbon fiber composite structure. 
     
     
       12. The blade of  claim 10 , wherein the suction side sheath and the pressure side sheath comprise titanium, stainless steel or nickel. 
     
     
       13. The blade of  claim 11 , wherein the root of the structural core includes circumferential faces that slope outwardly from the first and second core members to establish an external surface contour of the blade. 
     
     
       14. The blade of  claim 13 , wherein the at least one of the pressure and suction side sheaths is the pressure side sheath, and the central rib abuts an interior surface of the suction side sheath along an interface from the base to the tip, and the central rib and the interior surface of the suction side sheath are fixedly attached along the interface. 
     
     
       15. A fan blade for a gas turbine engine, comprising:
 a pressure side sheath having a leading edge portion and a trailing edge portion; 
 a suction side sheath secured to the pressure side sheath, the suction side sheath including a first suction side sheath edge configured to mate with a first pressure side sheath edge and a second suction side sheath edge configured to mate with a second pressure side sheath edge; 
 wherein the pressure side sheath and the suction side sheath form a continuous sheath that wraps around an interior section of the fan blade; 
 wherein at least one of the pressure and suction side sheaths includes a base, a tip, and a central rib extending spanwise from the base to the tip such that a first cavity and a second cavity are established on opposed sides of the central rib; and 
 a structural core having a first core member in the first cavity and a second core member in the second cavity, and the structural core including a root that interconnects the first and second core member. 
 
     
     
       16. The fan blade of  claim 15 , wherein the first suction side sheath edge extends from a suction side base of the suction side sheath to a suction side tip of the suction side sheath and wherein the first pressure side sheath edge extends from a pressure side base of the pressure side sheath to a pressure side tip of the pressure side sheath. 
     
     
       17. The fan blade of  claim 16 , wherein the second suction side sheath edge extends from the suction side base of the suction side sheath to the suction side tip of the suction side sheath and wherein the second pressure side sheath edge extends from the pressure side base of the pressure side sheath to the pressure side tip of the pressure side sheath. 
     
     
       18. The fan blade of  claim 17 , wherein the first cavity is positioned between the leading edge portion and the central rib, and the second cavity is positioned between the trailing edge portion and the central rib. 
     
     
       19. The fan blade of  claim 18 , wherein the structural core includes a root configured for attachment to a rotor. 
     
     
       20. The fan blade of  claim 19 , wherein the pressure and suction side sheaths are metallic. 
     
     
       21. The fan blade of  claim 20 , wherein:
 the root of the structural core defines an external surface contour of the blade; and 
 the pressure and suction side sheaths are attached along the central rib. 
 
     
     
       22. The fan blade of  claim 21 , wherein the root, the first core member and the second core member form a unitary, monolithic component constructed of a carbon fiber composite structure.